Augmented Subscleral Trabeculectomy With Beta Radiation and Mitomycin C in Egyptian Glaucoma Patients.

PURPOSE: Subscleral trabeculectomy is the most common surgical treatment for glaucoma. However, wound healing and scar formation may result in bleb fibrosis, leading to bleb failure. The healing response of the wound is reported to be the single most important risk factor in determining the final intraocular pressure (IOP) after glaucoma filtration surgery. Thus, we aimed to evaluate the effect of preoperative beta irradiation and intraoperative mitomycin C (MMC) treatment as combined adjuncts to subscleral trabeculectomy in the management of glaucoma in Egyptian patients. PATIENTS AND METHODS: This prospective, interventional, comparative masked clinical study was performed between October 2016 and January 2018. This study included 50 subjects, 25 of whom underwent trabeculectomy augmented by MMC intraoperatively and beta radiation preoperatively at the bleb area (patient group #1). The remaining 25 subjects underwent trabeculectomy with MMC alone (control group #2). Beta radiation was administered 5 to 7 days before the surgery as a single dose (1000 cGy) using a strontium-90 probe. MMC (0.2 mg/mL) was administered for 2 minutes. RESULTS: There was a statistically significant difference in postoperative IOP between the groups from the second week. Intraoperative hyphema occurred in 6 cases in the control group #2, whereas no intraoperative hyphema was observed in patient group #1; this difference was statistically significant. CONCLUSIONS: Subscleral trabeculectomy augmented by beta radiation and MMC gives greater control over IOP. Therefore, we recommend using beta radiation before trabeculectomy in patients who may have a high risk of developing conjunctival fibrosis.

Physical exercise and glaucoma: a review on the roles of physical exercise on intraocular pressure control, ocular blood flow regulation, neuroprotection and glaucoma-related mental health.

The benefits of physical exercise on health and well-being have been studied in a wide range of systemic and ocular diseases, including glaucoma, a progressive optic neuropathy characterized by accelerated apoptosis of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) and insufficient ocular perfusion have been postulated to be the two main theories in glaucoma development and progression. The effects of exercise in these two aspects have been demonstrated by numerous researches. A review in 2009 focusing on these two theories concluded that exercise results in transient IOP reduction but an inconsistent elevation in ocular perfusion. However, the majority of the studies had been conducted in healthy subjects. Over the past decade, technological advancement has brought forth new and more detailed evidence regarding the effects of exercise. Moreover, the neuroprotective effect of exercise by upregulation of neurotrophin and enhancement of mitochondrial function has been a focus of interest. Apart from visual impairment, the mental health issues in patients with glaucoma, which include anxiety and depression, should also be addressed. In this review, we mainly focus on publications from the recent years, so as to provide a comprehensive review on the impact of physical exercise on IOP, ocular perfusion, neuroprotection and mental health in patients with glaucoma.

GlyCAM1 negatively regulates monocyte entry into the optic nerve head and contributes to radiation-based protection in glaucoma.

BACKGROUND: We previously reported a profound long-term neuroprotection subsequent to a single radiation-therapy in the DBA/2J mouse model of glaucoma. This neuroprotection prevents entry of monocyte-like immune cells into the optic nerve head during glaucoma. Gene expression studies in radiation-treated mice implicated Glycam1 in this protection. Glycam1 encodes a proteoglycan ligand for L-selectin and is an excellent candidate to modulate immune cell entry into the eye. Here, we experimentally test the hypothesis that radiation-induced over-expression of Glycam1 is a key component of the neuroprotection. METHODS: We generated a null allele of Glycam1 on a DBA/2J background. Gene and protein expression of Glycam1, monocyte entry into the optic nerve head, retinal ganglion cell death, and axon loss in the optic nerve were assessed. RESULTS: Radiation therapy potently inhibits monocyte entry into the optic nerve head and prevents retinal ganglion cell death and axon loss. DBA/2J mice carrying a null allele of Glycam1 show increased monocyte entry and increased retinal ganglion cell death and axon loss following radiation therapy, but the majority of optic nerves were still protected by radiation therapy. CONCLUSIONS: Although GlyCAM1 is an L-selectin ligand, its roles in immunity are not yet fully defined. The current study demonstrates a partial role for GlyCAM1 in radiation-mediated protection. Furthermore, our results clearly show that GlyCAM1 levels modulate immune cell entry from the vasculature into neural tissues. As Glycam1 deficiency has a more profound effect on cell entry than on neurodegeneration, further experiments are needed to precisely define the role of monocyte entry in DBA/2J glaucoma. Nevertheless, GlyCAM1's function as a negative regulator of extravasation may lead to novel therapeutic strategies for an array of common conditions involving inflammation.

Radiation pretreatment does not protect the rat optic nerve from elevated intraocular pressure-induced injury.

PURPOSE: Optic nerve injury has been found to be dramatically reduced in a genetic mouse glaucoma model following exposure to sublethal, head-only irradiation. In this study, the same radiation treatment was used prior to experimental induction of elevated intraocular pressure (IOP) to determine if radiation is neuroprotective in another glaucoma model. METHODS: Episcleral vein injection of hypertonic saline was used to elevate IOP unilaterally in two groups of rats: (1) otherwise untreated and (2) radiation pretreated, n > 25/group. Intraocular pressure histories were collected for 5 weeks, when optic nerves were prepared and graded for injury. Statistical analyses were used to compare IOP history and nerve injury. The density of microglia and macrophages in two nerve head regions was determined by Iba1 immunolabeling. RESULTS: Mean and peak IOP elevations were not different between the two glaucoma model groups. Mean optic nerve injury grades were not different in glaucoma model optic nerves and were equivalent to approximately 35% of axons degenerating. Nerves selected for lower mean or peak IOP elevations did not differ in optic nerve injury. Similarly, nerves selected for lower injury grade did not differ in IOP exposure. By multiple regression modeling, nerve injury grade was most significantly associated with mean IOP (P < 0.002). There was no significant effect of radiation treatment. Iba1+ cell density was not altered by radiation treatment. CONCLUSIONS: In contrast to previous observations in a mouse genetic glaucoma model, head-only irradiation offers the adult rat optic nerve no protection from optic nerve degeneration due to chronic, experimentally induced IOP elevation.

Meta-analysis of beta radiation augmentation for trabeculectomy - results in distinct ethnic groups.

PURPOSE: To conduct a systematic review with meta-analysis on the efficacy of trabeculectomy (TREC) followed by beta irradiation (BRT/TREC) compared to TREC alone for glaucoma in terms of intraocular pressure (IOP) control and adverse effects of treatment in different ethnic groups. METHODS: A meta-analysis of randomized controlled trials (RCT) was performed comparing adjunct BRT treatment for glaucoma with standard TREC after 12 months. The MEDLINE, EMBASE, LILACS, and Cochrane Library databases, Trial registers, bibliographic databases and recent studies of relevant journals were searched. Two reviewers independently reviewed relevant reports and the references from these reports were searched for additional trials, using guidelines set by QUOROM statement criteria. RESULTS: Of a total of 1,350 citations, eight studies (five cohorts, three randomized) were identified and only 3 RCT were included in this meta-analysis. Higher IOP reductions were verified in the BRT arm compared to the control arm (mean difference=1.68 mmHg, 95% CI= 0.61-2.68, P=0.002). Uncontrolled postoperative IOP (>21 mmHg) was less frequent when BRT was used (BRT/ TREC arm) compared to the control arm (38/218=17.4% versus 9/239=3.8%; OR=6.7; 95% CI 3.2-14.3, P<0.0001). Although better IOP control was observed in all patients treated with adjuvant BRT, only Black patients displayed a significant difference (P=0.005). There were no significant differences between the BRT and control arms regarding loss of visual acuity, postoperative complications and necessity of cataract surgery. CONCLUSION: Adjunct BRT increases the success rate of TREC, with better results in non Caucasian patients, and does not influence the occurrence of postoperative complications.

Meta-analysis of beta radiation augmentation for trabeculectomy - results in distinct ethnic groups / Meta-análise da trabeculectomia potencializada pela radiação beta - resultados em grupos étnicos distintos

PURPOSE: To conduct a systematic review with meta-analysis on the efficacy of trabeculectomy (TREC) followed by beta irradiation (BRT/TREC) compared to TREC alone for glaucoma in terms of intraocular pressure (IOP) control and adverse effects of treatment in different ethnic groups. METHODS: A meta-analysis of randomized controlled trials (RCT) was performed comparing adjunct BRT treatment for glaucoma with standard TREC after 12 months. The MEDLINE, EMBASE, LILACS, and Cochrane Library databases, Trial registers, bibliographic databases and recent studies of relevant journals were searched. Two reviewers independently reviewed relevant reports and the references from these reports were searched for additional trials, using guidelines set by QUOROM statement criteria. RESULTS: Of a total of 1,350 citations, eight studies (five cohorts, three randomized) were identified and only 3 RCT were included in this meta-analysis. Higher IOP reductions were verified in the BRT arm compared to the control arm (mean difference=1.68 mmHg, 95 percent CI= 0.61-2.68, P=0.002). Uncontrolled postoperative IOP (>21 mmHg) was less frequent when BRT was used (BRT/ TREC arm) compared to the control arm (38/218=17.4 percent versus 9/239=3.8 percent; OR=6.7; 95 percent CI 3.2-14.3, P<0.0001). Although better IOP control was observed in all patients treated with adjuvant BRT, only Black patients displayed a significant difference (P=0.005). There were no significant differences between the BRT and control arms regarding loss of visual acuity, postoperative complications and necessity of cataract surgery. CONCLUSION: Adjunct BRT increases the success rate of TREC, with better results in non Caucasian patients, and does not influence the occurrence of postoperative complications.

OBJETIVO: Realizar uma revisão sistemática com meta-análise sobre a eficácia da trabeculectomia (TREC), seguida ou não por irradiação beta (BRT/TREC) para o tratamento do glaucoma, em termos de controle da pressão intraocular (PIO) e de efeitos adversos, em diferentes grupos étnicos. MÉTODOS: Uma meta-análise de ensaios clínicos randomizados (RCT) foi realizada, comparando os resultados de 12 meses da TREC com o uso adjuvante de BRT, com aqueles da TREC padrão. Foram fontes de pesquisa as bases de dados MEDLINE, EMBASE, LILACS, Cochrane, além de sítios de registro de ensaios clínicos, estudos recentes em revistas da área e outras bases de dados bibliográficos. Dois revisores avaliaram independentemente publicações relevantes e as referências desses trabalhos foram pesquisadas para procura de ensaios adicionais, de acordo com as diretrizes estabelecidas pelos critérios do QUOROM. RESULTADOS: De um total de 1.350 citações, oito estudos (cinco coortes e três aleatorizados) foram identificados e apenas 3 RCT foram incluídos nesta meta-análise. Maiores reduções na PIO foram verificadas no braço de estudo da BRT, comparado com o braço controle (diferença média=1,68 mmHg, 95 por cento CI= 0,61-2,68, P=0,002). A frequência de PIO pós-operatória não controlada (>21 mmHg) foi menor quando utilizada a BRT (BRT/TREC) em relação ao grupo controle (38/218 =17,4 por cento versus 9/239 =3,8 por cento; OR= 6,7 IC 95 por cento 3,2 14,3, P<0,0001). Apesar do melhor controle da PIO ter sido observada em todos os pacientes do braço BRT, apenas os pacientes negros apresentaram uma diferença significativa (P=0,005). Não houve diferenças significativas entre os braços BRT e controle, em termos de perda da acuidade visual, complicações pós-operatórias e necessidade de cirurgia de catarata. CONCLUSÃO: O uso de BRT adjuvante aumenta a taxa de sucesso da TREC, com melhores resultados em pacientes não-caucasianos, não influenciando a ocorrência de complicações pós-operatórias.

[Comparative hemodynamic characteristics of patients with the organ of vision subjected to low-intensity laser radiation of the green and red wavelengths].

This comparative study was designed to evaluate effect of low-intensity speckle laser radiation in the green and red wavelengths on intraocular hemodynamics in 202 patients (202 eyes) with retinal vascular problems and without them. Irradiation was performed using "Izumrud" and "Rubin" adapters for an AMO-ATOS unit. Peak systolic velocity and peripheral resistance index in posterior short ciliary arteries and central retinal artery were measured. It was shown for the first time that green speckle laser radiation (wavelength 535 nm) has more pronounced (compared with the red light) effect on intraocular hemodynamics; thereby, it makes a greater contribution to the improvement of the visual function (e.g. in the case of glaucoma) and to the widening of the fields of vision.

Experimental study on low pulse energy processing with femtosecond lasers for glaucoma treatment.

The feasibility of low energy processing in ocular tissues with femtosecond laser sources was investigated in this research. One laser source was a femtosecond amplifier, and the other was a femtosecond oscillator. The amplifier used in this experiment was a CPA-2001 (Clark-MXR, Inc), with 150 fs pulse duration and 1 kHz repetition rate. The femtosecond oscillator (model 900-B Mira) produced a 200 fs pulse duration and a 76 MHz repetition rate. Both these two laser systems operated at 800 nm wavelengths. Firstly, the pulse intensity thresholds in water produced by the two laser sources were compared. The optical breakdown probability analysis shows that the pulse energy threshold achieved by the oscillator was less than 10% of that achieved by the amplifier. Then, the non-linear propagation of the femtosecond pulses in the ocular tissues was studied with the femtosecond oscillator. The results showed a potential for pulse energy processing at the nanojoule level with a femtosecond oscillator in glaucoma treatment.

Potential use of P-32 ophthalmic applicator: Monte Carlo simulations for design and dosimetry.

Postoperative beta-irradiation after pterygium excision has been considered a valuable therapeutic procedure to reduce the recurrence rate. Recently, it was reported that beta-irradiation also substantially reduced the risk of surgical failure after glaucoma surgery. Pure beta-irradiation using a 90Sr/Y applicator has been almost exclusively used for this purpose. As an alternative to 90Sr/Y beta-irradiation, we propose treatment with betas of a 32P source. While 32P has a lower maximum energy (1.71 MeV) than 90Sr/Y (2.27 MeV), it has an average energy comparable to that of 90Sr/Y. Furthermore, it can be produced easily in a nuclear reactor by neutron activation and is considered a less hazardous material. Monte Carlo simulations for the dosimetry of proposed 32P applicators were performed using the MCNP5 code. The structure and dimension of the 32P applicators were based on those of the 90Sr/Y applicators currently available, while medical plastic encapsulation and liquid source were chosen to enhance beta-dose to the surface of the conjunctiva. The 32P applicator showed that the surface dose distribution (up to 0.75 mm depth) is very similar to that of 90Sr/Y. However, beyond 0.75 mm depth, the 32P doses decrease with depths more rapidly than 90Sr/Y doses. In order to achieve the same surface dose rate, the required 32P activity is about three times that for a 90Sr/Y applicator. We conclude that the proposed 32P applicator can deliver therapeutic doses to the target lesion while sparing the lens better than the 90Sr/Y applicator. The 32P activity required to deliver therapeutic doses can be produced in a 30 MW reactor available at the Korea Atomic Energy Research Institute.

Iridotomías con Yag-láser en gemelos heterocigóticos / Yag laser iridotomy applied in heterozygotic twins

Se informa de dos gemelos heterocigóticos de 28 años de edad que al acudir a consulta de oftalmología se les constató un ángulo camerular estrecho, sin hipertensión ocular ni alteraciones de sus campos visuales. Se decidió la realización de iridotomías con láser como prevención de cierre angular intermitente o agudo. Después de realizado este proceder y hasta la actualiadad se ha mantenido un seguimiento sistematico al caso.

This paper reported the case of two heterozygotic twins aged 28 years, who went to the Ophthalmological Service and were diagnosed with a close camerular angle, without suffering either ocular hypertension or visual field alterations. Nd: Yag laser iridotomies was indicated to prevent intermittent or acute angle closure. After this procedure up to the present, this case has been systematically followed-up.

[Secondary glaucoma treatment by means of Leksell gamma knife]. / Lécba sekundárního glaukomu Leksellovým gama nozem.

The authors followed up 107 eyes of 103 patients with the diagnosis of painful secondary glaucoma treated by irradiation of the ciliary body by means of Leksell gama knife (LGK Elekta Instruments AB). The goal was to decrease patient's subjective problems in to the treatment resistant and painful stages using non-invasive stereo tactic neurosurgical procedure. The final version of the irradiation schedule uses 8 mm collimators and the irradiation dose in blind eyes is 40 Gy at the maximum and 20 Gy at the peripheral treating 50% isodose; in partly sighted eyes it is 30 Gy at the maximum and 15 Gy at the peripheral treating 50% isodose. The follow up period was 3-80 months, (average 26 months). The lowering of the intraocular pressure to the not painful level was achieved in 56 eyes (52.2%) during the period of 1-8 weeks (median 4 weeks). The total disappearing of the pain after the treatment was noticed in 71 eyes (66.4%), partial reduction of the pain in 31 eyes (29%), and no effect was observed in 5 eyes. In all cases of neovascularization at least some decrease was noticed. The antiglaucomatous therapy was reduced in 42 patients (39.3%) 2-3 months after the irradiation, unchanged remained in 51 patients (47.7%). The stereotactic radiosurgical destruction of the ciliary body by means of Leksell gama knife, may reduce the pain, the intraocular pressure, and extensive medicament treatment in secondary painful glaucoma.

High-dose radiation with bone marrow transfer prevents neurodegeneration in an inherited glaucoma.

Here, we show that high-dose gamma-irradiation accompanied with syngeneic bone marrow transfer can confer complete protection against glaucoma in a mouse model. Because bone marrow genotype was unaltered by this procedure, it was not the causative agent. The neuroprotection is robust and highly reproducible. Glaucoma-prone DBA/2J mice received a single treatment at 5-8 weeks of age and were protected from glaucomatous retinal ganglion cell degeneration out to 14 months of age (oldest assessed). By 12-14 months, retinal ganglion cell degeneration is usually very severe and essentially complete in the majority of untreated DBA/2J mice. To assess reproducibility, three groups of mice were treated at different times, and the results were essentially the same each time. Considering all experiments, the vast majority of treated mice had no detectable glaucomatous neurodegeneration. A beneficial effect of treatment including high-dose radiation is unprecedented, and we are not aware of any other neuroprotective effects this substantial. Because of the robust protective effect, this treatment offers another tool for studying mechanisms of neuroprotection.

Femtosecond laser for glaucoma treatment: a study on ablation energy in pig iris.

Safe and effective laser ophthalmic surgery requires a fine balance between the efficiency of laser delivered and the degree of collateral side damage. The laser-ocular tissue interaction process is reliant on three main variables, namely, wavelength, pulse duration, and deposited energy. A certain amount of energy is needed to achieve ablation, while too much energy can result in unwanted collateral thermal damage. In our work the relationship between energy deposition and ablation effect is studied by an in-vitro experiment using an 800 nm wavelength 150 fs-pulse-duration laser system. This experiment aims to validate the probability of decreasing the supplied energy during glaucoma surgery by femtosecond laser. Our results show that less energy is needed using femtosecond laser than that using a longer pulse laser.

Beta irradiation: new uses for an old treatment: a review.

Beta radiation has a long history as a treatment modality in ophthalmology. It is a convenient and practical method of applying radiation and has the advantage of minimal tissue penetration. There has been a recent resurgence in the use of beta radiation in other areas in medicine, such as the prevention of restenosis after coronary artery stenting. Beta radiation has been shown in vitro and in vivo to inhibit proliferation of human Tenon's fibroblasts, which enter a period of growth arrest but do not die. Effects on the cell cycle controller p53 have been shown to be important in this process. In ophthalmology, beta radiation has been used widely for the treatment of pterygium and is under evaluation for treatment of age-related macular degeneration and for controlling wound healing after glaucoma drainage surgery. In this latter role, beta radiation may be particularly appropriate for use in developing countries to improve the results of trabeculectomy while potentially avoiding some of the side effects of other antimetabolites.

Telemedicine techniques can be used to facilitate the conduct of multicentre trials.

A multicentre randomized controlled trial was established in Pretoria, Bloemfontein and Edendale in South Africa, and coordinated from London. The purpose of the trial was to determine the efficacy of low-dose beta irradiation of glaucoma. Five communication modalities (telephone, fax, e-mail, videoconferencing and face-to-face meetings) were examined in terms of their benefits in a multicentre trial. The eight stages of the multicentre trial examined were: set-up and training, recruitment, standardization, patient management, data transmission, update and data dissemination, clinical follow-up and monitoring, and publication. On four-point Likert scales for rating the usefulness of the communication modalities at each of the eight stages of the trial (from 0 = not useful to 3 = very useful; maximum score 24) the telephone was given a total score of 10, fax 9, e-mail 13, videoconferencing 15 and face-to-face meetings 9. Telemedicine techniques offer considerable benefits in the coordination of multicentre trials by improving data collection, maintaining the efficacy and monitoring of trials, while potentially offering reduced costs in terms of travel and time. The realtime scrutiny of patient records helps to ensure data uniformity and completeness of data collection. Videoconferencing was most useful when considered as one of several communication tools that can be used to improve the effectiveness of a service or process.

[Successful irradiation of ciliary processes with electrons in therapy refractory aphakic glaucoma]. / Erfolgreiche Bestrahlung der Ziliarzotten mit Elektronen bei therapieresistentem Aphakieglaukom.

BACKGROUND: Successful radiation was already reported by Genée and Weitzel (1968): Electrons from a Betatron were used for irradiation of the ciliary epithelium to lower aqueous humor secretion. To our knowledge, no other paper on this topic has been published so far. PATIENT: A 26-year-old man had history of concussion trauma and cataract surgery in childhood. In adult age, cataract surgery and retinal operations were followed by numerous surgical procedures and maximal medical treatment because of a secondary glaucoma. The patient refused further surgical and medical treatment with the exception of the administered systemic carbo-anhydrase inhibitor. Because of severe side-effects caused by the acetozolamide, irradiation of the ciliary processes with electrons, emitted from a linear accelerator, was performed. The total amount of 12 Gy both on the nasal and on the temporal side of the ciliary body was fractionated in several sessions. RESULTS: During a follow-up of 22 months without medication, the mean value of i.o. pressure was 22.1 mm Hg. The patient is doing well, corrected VA is 0.8. CONCLUSION: Irradiation of the ciliary processes with electrons for lowering aqueous humor secretion was effective in an otherwise non treatable case of glaucoma.

Trabeculectomy combined with beta irradiation for congenital glaucoma.

Sixty-six eyes with congenital glaucoma were subjected to trabeculectomy between July 1975 and June 1989 are presented. Thirty-one were treated with beta irradiation at the time of surgery with a strontium-90 applicator; 35 were not treated with beta irradiation. The usual dose was 750 rad. Analysis was limited to three years because of the shorter follow-up of the irradiated eyes. Failure in the two groups was compared statistically. When failure was categorised as IOP greater than 21 mm Hg, beta irradiation was found to be significantly protective with an adjusted risk ratio of 0.31 (95% confidence interval 0.11-0.90, p less than 0.05). Failure categorised as the need for additional medical treatment or further surgery showed significant protection with an adjusted risk ratio of 0.33 (confidence interval 0.12-0.94, p less than 0.05). Multiple regression models were used for the analysis of intraocular pressure; beta irradiation was associated with a significantly lower IOP at six months, one year, and three years (p less than 0.05). Other factors identified as being associated with a reduced failure rate or lower IOP were: no previous topical glaucoma medications: age over seven years; lack of previous surgery involving the conjunctiva. The results indicate that beta irradiation may have a beneficial effect on the prognosis of trabeculectomy in children with congenital glaucoma. However, because of the retrospective and observational nature of the study, the results must be regarded as tentative.

The effect of topical dexamethasone and preoperative beta irradiation on a model of glaucoma fistulizing surgery in the rabbit.

We studied the effect of topical dexamethasone (1%) and preoperative beta irradiation on a model of glaucoma fistulizing surgery in the rabbit. Intraocular pressure and gross facility of aqueous outflow following surgery were not influenced by either treatment, although blebs persisted longer in the irradiated eyes. Steroids reduced clinically observable inflammation as well as the number of inflammatory cells identifiable by microscopy. Fibroblast production temporarily slowed, and ultra-structural examination demonstrated lipid-filled vacuoles and dilated mitochondria in these eyes. Also, the scar was thinner at 24 days. Beta irradiation delayed wound healing and the scar was thinner in the early postoperative stages, but the light microscopic appearance of the scar was unaltered at 59 days. Inflammation was more pronounced initially, with abundant fibrin in the wound. Recovery of the conjunctival epithelium was delayed. The delay in fibroblast recruitment and wound contraction, the thinner scar tissue, and the increased survival of the bleb are all factors that suggest that beta irradiation may be a useful adjunct to glaucoma surgery.

[The mechanism of action of laser stimulation of the eye]. / K mekhanizmu deistviia lazerstimuliatsii organa zreniia.

The mechanism of action of helium-neon laser stimulation has been studied in 26 eyes of 15 patients with dystrophic diseases of the eye and on the ground of 63 lymphangiographic investigations of the same patients. It was found that low-energy helium-neon laser stimulation (0.05-0.5 mWt/cm2) has a positive effect on restoration of visual functions. Lymphangiographic investigations have revealed a new biological phenomenon--activation of disturbed lymphatic flow under the action of a specially organized laser radiation. The results obtained confirm the earlier hypothesis (M. M. Krasnov et al., 1982) that under the action of laser radiation a normal physiologic system purifying the retina from disintegrated products is engaged into action.